Aircraft fire extinguishing device and mounting method

CROSS-REFERENCE TO RELATED APPLICATIONS

p-0002This application claims priority to and the benefit of French Application No. 09 51481 filed on 10 Mar. 2009, the disclosures of which are incorporated herein by reference in its entirety.

p-0003The aspects of the disclosed embodiments relate to a firefighting device, called an extinguisher. More particularly, the disclosed embodiments relate to a system for installation and removal of reservoirs of extinguishing agent of an aircraft fire extinguisher.

BACKGROUND

p-0004In modern airplanes, more particularly civilian transport airplanes, fire extinguishers are provided.

p-0005Such devices, known for example from the Application FR 2864905, besides means for detecting the start of a fire and for controlling said device, have one or more reservoirs of extinguishing agent feeding a network to distribute the extinguishing agent to spray nozzles.

p-0006The reservoirs of extinguishing agent contain the extinguishing agent itself and means for pressurizing this extinguishing agent inside the reservoir, by means of a propelling agent, to permit its distribution at the desired time.

p-0007In practice, the reservoirs of extinguishing agent are often installed close to areas at risk of fire, such as hot zones where fuel circulates in the environment of the engines, or such as areas in which the impossibility of access in flight does not allow any other means of firefighting, for example the cargo compartments.

p-0008As an illustration that is particularly suitable for the applications of the disclosed embodiments, the case of an installation of a reservoir of fire extinguishing agent in an engine pylon is considered in the following description.

p-0009Thus, in airplanes that have engines attached beneath the wings by suspension pylons, it is beneficial to fasten the extinguishing agent reservoirs of the engine fire extinguishers inside the pylons, despite the numerous systems including cables and pipes passing through inside the pylons, and the size of the pylons which is reduced so as not to penalize the aerodynamics of the airplane.

p-0010Also, the extinguishing agent reservoirs must be the object of frequent checks in situ and in the workshop to verify their good condition, the volumes of extinguishing agent and of propelling agent inside them, and to be regularly reconditioned or replaced in case of their use.

p-0011Accordingly, the extinguishing agent reservoirs are necessarily capable of being taken down, and to that end, in particular when they are installed in a pylon, they are fastened to a fire extinguisher hanger structure, itself fastened to the inside of the principal structure of the pylon, from where said reservoirs can be removed or introduced through openings made in the side walls of the pylon, which openings are limited to a strict minimum because of the fact that said walls are generally working walls.

p-0012An example of a known extinguishing agent reservoir <b>1</b> is shown in <figref idrefs="DRAWINGS">FIG. 1</figref><i>a</i>. An example of a hanger structure <b>2</b> is shown in <figref idrefs="DRAWINGS">FIG. 1</figref><i>b </i>without the other parts of the principal structure of the pylon.

p-0013In all of the present description, the references to positioning the various elements are made considering said elements installed in a pylon of an airplane immobile on the ground; this is the case inter alia for the references “lower”, “upper”, “horizontal”, “vertical”, etc.

p-0014The hanger structure <b>2</b> in the pylon structure occupies principally a space located above the reservoirs <b>1</b>.

p-0015The hanger structure <b>2</b> has an essentially horizontal chassis <b>20</b>, beneath which are fastened a plurality of longitudinal crossbars <b>21</b>. Each of said crossbars <b>21</b> has an essentially horizontal lower edge, and a reservoir <b>1</b> is fastened on the lower bearing surfaces of said lower edges of two adjacent crossbars <b>21</b>.

p-0016A rail <b>22</b> is associated with each of said crossbars and forms a lateral guide beneath the crossbar <b>21</b> with which it is associated, which extends along said crossbar. For each pair of adjacent crossbars <b>21</b>, two facing lateral slider bars are thus formed.

p-0017The extinguishing agent reservoir <b>1</b> has four metal fittings <b>10</b> intended to be fastened by fasteners, such as screws and nuts, to the lower bearing surfaces of the crossbars <b>21</b> of the hanger structure <b>2</b>, which are positioned on the upper spherical head of the reservoir <b>1</b>.

p-0018Each fitting <b>10</b> protrudes laterally on said upper spherical head, and has an edge forming a tenon, whose shape and dimensions are suitable for permitting said edge to slide in a lateral guide of the hanger structure <b>2</b>. Each fitting <b>10</b> has an upper support bearing surface that is essentially planar and horizontal, to lean against the lower bearing surface of a crossbar <b>21</b> of the hanger structure <b>2</b>.

p-0019As shown in <figref idrefs="DRAWINGS">FIG. 1</figref><i>c</i>, each reservoir <b>1</b> is installed beneath the hanger structure <b>2</b> by engaging the edges of the metal fittings <b>10</b> in the facing lateral guides of a pair of adjacent crossbars <b>21</b>. Said edges are placed onto the rails <b>22</b> of said lateral guides, and slide on said rails to penetrate into said engine pylon.

p-0020However, the engagement of the edges of the fittings <b>10</b> in the lateral guides to place the reservoir in the pylon is not easy, because of the dimensions of the openings made in the side walls of the pylon. The assembly is also not easy because such a reservoir <b>1</b> is generally rather voluminous (diameter of the order of 30 centimeters) and heavy (weight greater than 20 kilograms), and has to be carried at arm's length by one or more operators during its installation in the inside restricted space of the pylon.

p-0021It can be understood that new means are necessary to facilitate installation and removal of airplane fire extinguisher reservoirs.

SUMMARY

p-0022The disclosed embodiments propose to solve the aforementioned problems by means of an extinguisher that comprises a hanger structure and at least one extinguishing agent reservoir, with the reservoir being hung beneath the hanger structure by fittings held by fasteners to said hanger structure. According to the disclosed embodiments, the reservoir comprises means of suspension, and the hanger structure comprises complementary carriers for the means of suspension, with the means of suspension and the carriers being such that:

p-0023when the fasteners are tightened, the reservoir is in a position, called the “operational position”, in which the fittings are integral with the hanger structure and the means of suspension and the carriers are engaged without contact,

p-0024when the fasteners are taken out, the reservoir is in a position, called the “intermediate position”, in which the fittings are free and the reservoir is suspended by interaction between the means of suspension and the carriers.

p-0025The means of suspension are preferably made in an upper part of the reservoir, essentially in a position vertical from a center of gravity of the reservoir. The means of suspension and the carriers are preferably made so that the intermediate position is adjacent to the operational position.

p-0026In a preferred embodiment, the means of suspension comprise a free end in the form of a hook, preferably associated with carriers that comprise a ring.

p-0027In another preferred embodiment, the means of suspension comprise a free end with a T-shaped cross section, preferably associated with carriers that comprise a longitudinal guide.

p-0028The means of suspension advantageously comprise only one free end.

p-0029According to the disclosed embodiments, a procedure for fastening a reservoir of extinguishing agent of such an extinguisher includes the following steps:

p-0030a step of suspending the reservoir on the hanger structure during which the means of suspension of the reservoir are engaged in the carriers of the hanger structure and interact with said carriers so that the reservoir is in an intermediate suspended position in which the metal fittings are free,

p-0031a step of fastening the reservoir beneath the hanger structure in which the fittings of the reservoir are fastened to the hanger structure by tightening the fasteners.

BRIEF DESCRIPTION OF THE DRAWINGS

p-0032The following description of examples of the disclosed embodiments is given with reference to the drawings, in which identical references designate identical or analogous elements, which show in a non-limiting way:

p-0033<figref idrefs="DRAWINGS">FIG. 1</figref><i>a</i>: already cited, a reservoir pursuant to the prior art,

p-0034<figref idrefs="DRAWINGS">FIG. 1</figref><i>b</i>: already cited, a hanger structure pursuant to the prior art,

p-0035<figref idrefs="DRAWINGS">FIG. 1</figref><i>c</i>: already cited, a schematic representation illustrating the installation of the reservoir of <figref idrefs="DRAWINGS">FIG. 1</figref><i>a </i>in the hanger structure of <figref idrefs="DRAWINGS">FIG. 1</figref><i>b, </i>

p-0036<figref idrefs="DRAWINGS">FIG. 2</figref><i>a</i>: a schematic representation of the front side of a reservoir according to a first embodiment of the disclosed embodiments,

p-0037<figref idrefs="DRAWINGS">FIGS. 2</figref><i>b </i>and <b>2</b><i>c</i>: two schematic representations in perspective, illustrating the installation of the reservoir of <figref idrefs="DRAWINGS">FIG. 2</figref><i>a </i>in a hanger structure according to the disclosed embodiments,

p-0038<figref idrefs="DRAWINGS">FIG. 3</figref><i>a</i>: a schematic representation in perspective of a reservoir according to a second embodiment of the disclosed embodiments,

p-0039<figref idrefs="DRAWINGS">FIGS. 3</figref><i>b </i>and <b>3</b><i>c</i>: two schematic representations in perspective, illustrating the installation of the reservoir of <figref idrefs="DRAWINGS">FIG. 3</figref><i>a </i>in a hanger structure according to the disclosed embodiments.

p-0040<figref idrefs="DRAWINGS">FIG. 4</figref>: a schematic representation illustrating the installation of the reservoir in a pylon of an aircraft.

DETAILED DESCRIPTION

p-0041The disclosed embodiments are applicable to any fire extinguisher for aircraft, more particularly extinguishers lodged in areas of the aircraft that are inaccessible in flight, such as engine fire extinguishers or cargo compartment fire extinguishers.

p-0042The non-limiting case of an extinguisher <b>5</b> intended to be fastened in an engine pylon <b>5</b> of an airplane <b>7</b> (shown in <figref idrefs="DRAWINGS">FIG. 4</figref>) is considered for the needs of the description of embodiments of the disclosed embodiments.

p-0043According to the disclosed embodiments, an extinguisher has at least one reservoir <b>3</b> for extinguishing agent and a hanger structure <b>4</b> intended to be fastened to the inside of a principal structure of an engine pylon.

p-0044The extinguishing agent reservoir <b>3</b>, for example, has an essentially spherical shape and has metal fittings <b>300</b>, <b>301</b><i>a</i>, <b>301</b><i>b </i>intended to be integrated with the hanger structure <b>4</b> by fasteners.

p-0045For the needs of the description, a frame of reference with three axes X, Y, and Z, is associated with the extinguisher:

p-0046the Z axis is essentially vertical and points upward when the extinguisher is installed in an airplane immobile on the ground,

p-0047the Y axis is perpendicular to the Z axis and is oriented in a longitudinal direction along which the reservoir <b>3</b> is inserted into the hanger structure <b>4</b>,

p-0048the X axis is perpendicular to the Y and Z axes and forms a plane with the Y axis that is considered to be essentially horizontal when the extinguisher is installed in an airplane immobile on the ground.

p-0049The hanger structure <b>4</b> according to the disclosed embodiments has a chassis <b>40</b>, essentially horizontal in the non-limiting examples shown in the Figures, and other elements described below to which the metal fittings <b>300</b>, <b>301</b><i>a</i>, <b>301</b><i>b </i>of the reservoir <b>3</b> are fastened by fasteners, not shown.

p-0050The position of the reservoir <b>3</b> when it is fastened to the hanger structure <b>4</b> is called the “operational position.”

p-0051According to the disclosed embodiments, the reservoir <b>3</b> has means of suspension <b>31</b> and the hanger structure <b>4</b> has carriers <b>41</b> complementary to said means of suspension.

p-0052The means of suspension <b>31</b> of the reservoir <b>3</b>, when they interact with the carriers <b>41</b> of the hanger structure <b>4</b>, permit said reservoir to be suspended on said hanger structure in a position called the “intermediate position,” in which the metal fittings <b>300</b>, <b>301</b><i>a</i>, <b>301</b><i>b </i>are free and do not transmit any forces to said hanger structure.

p-0053In a preferred embodiment, the means of suspension <b>31</b> of the reservoir <b>3</b> extends essentially vertically from the upper spherical head of the reservoir <b>3</b> and have a free end <b>31</b><i>a </i>with a T-shaped cross section in a plane parallel to an XZ plane containing the X and Z axes, with said free end <b>31</b><i>a </i>being in a position essentially vertical from the center of gravity of the reservoir <b>3</b>.

p-0054In the non-limiting example shown in <figref idrefs="DRAWINGS">FIG. 2</figref><i>a</i>, the means of suspension <b>31</b> extends between said free end <b>31</b><i>a </i>and an end integral with the upper spherical head of the reservoir <b>3</b>, along an axis G passing through the center of gravity of said reservoir and parallel to the Z axis.

p-0055More generally, it is necessary for the width of the free end <b>31</b><i>a</i>, measured along the X axis, to assume two values along the G axis, called the “small width” and the “large width”, with said small width being on the side of the end integral with the reservoir <b>3</b>, and said large width being on the side opposite said reservoir.

p-0056The carriers <b>41</b> of the hanger structure <b>4</b>, complementary to the means of suspension <b>31</b> with a T-shaped free end <b>31</b><i>a </i>has a longitudinal guide <b>41</b><i>a </i>in the example shown, securely fastened beneath the chassis <b>40</b>, visible in <figref idrefs="DRAWINGS">FIGS. 2</figref><i>b </i>and <b>2</b><i>c. </i>

p-0057The guide <b>41</b><i>a </i>is a principally hollow element with an internal width measured along the X axis larger than the large width of the free T-shaped end <b>31</b><i>a </i>of the means of suspension <b>31</b>, which has a horizontal groove in its lower part whose width is greater than the small width of the T-shaped free end <b>31</b><i>a </i>and smaller than the large width of said free end.

p-0058As shown in <figref idrefs="DRAWINGS">FIG. 2</figref><i>b </i>and <figref idrefs="DRAWINGS">FIG. 2</figref><i>c</i>, the guide <b>41</b><i>a </i>is open at one end through which the free T-shaped end <b>31</b><i>a </i>penetrates into the guide by moving along the direction of the Y axis. When the T-shaped free end <b>31</b><i>a </i>is engaged in the guide <b>41</b><i>a</i>, the reservoir <b>3</b> is suspended on the hanger structure <b>4</b> because the width of the groove is smaller than the large width of said free end, and said reservoir can slide along said guide.

p-0059The structural characteristics of the guide <b>41</b><i>a </i>and of the linkage of said guide with the chassis <b>40</b> are defined to assure sufficient mechanical strength to support the weight of the reservoir <b>3</b> filled with extinguishing agent and propelling agent.

p-0060The position of the guide <b>41</b><i>a </i>beneath the chassis <b>40</b> is such that an intermediate position of the reservoir <b>3</b> adjacent to the desired operational position can be obtained by said reservoir moving along said guide.

p-0061“Intermediate position adjacent to the operational position” means that the motions necessary to pass from one to the other have a maximum amplitude of the order of several centimeters, and preferably of the order of one centimeter or less.

p-0062The reservoir <b>3</b>, for example, has four metal fittings <b>300</b> of the same type as the metal fittings of the reservoir <b>1</b> described with reference to <figref idrefs="DRAWINGS">FIG. 1</figref><i>a. </i>

p-0063Each metal fitting <b>300</b> protrudes laterally from said upper spherical head, and has an upper bearing surface geometrically fitted to a lower bearing surface of a lower edge of a crossbar <b>42</b> on which said upper surface makes contact, with each reservoir <b>3</b> being attached to the lower edges of two adjacent crossbars <b>42</b>. The fittings <b>300</b> and the crossbars have paired holes for the passage of fasteners of known type, not shown in the Figures.

p-0064More generally, other forms of fittings known to one skilled in the art can be combined with this embodiment of the means of suspension <b>31</b> and the carriers <b>41</b>.

p-0065In another preferred embodiment, the means of suspension <b>31</b> of the reservoir <b>3</b> protrude vertically from the upper spherical head of the reservoir <b>3</b>, and have a free end <b>31</b><i>b </i>in the form of a hook curved toward the back of the reservoir <b>3</b>, with the free end <b>31</b><i>b </i>being located in a position essentially vertical from the center of gravity of the reservoir <b>3</b>.

p-0066“Toward the back of the reservoir” means toward a side of said reservoir that is engaged first of all in the hanger structure <b>4</b> during its installation, opposite from a front side corresponding to the side by which an operator holds said reservoir, for example by means of handles <b>32</b>.

p-0067In the non-limiting example shown in <figref idrefs="DRAWINGS">FIG. 3</figref><i>a</i>, the means of suspension <b>31</b> extend between an end integral with the upper spherical head of the reservoir and said free end <b>31</b><i>b </i>along the G axis.

p-0068The carriers <b>41</b> of the hanger structure <b>4</b> complementary to the means of suspension <b>31</b> have a free end <b>31</b><i>b </i>in the form of a hook, and in the example shown they have a ring <b>41</b><i>b </i>securely fastened beneath the chassis <b>40</b>. In the non-limiting example shown in <figref idrefs="DRAWINGS">FIG. 3</figref><i>b </i>and <figref idrefs="DRAWINGS">FIG. 3</figref><i>c</i>, the ring <b>41</b><i>b </i>has a U shape.

p-0069Other shapes are feasible for the ring <b>41</b><i>b </i>as long as they are complementary to the hook shape of the free end <b>31</b><i>b </i>and permit the suspension of the reservoir <b>3</b> by engagement of said free end in said ring. The structural characteristics of the ring <b>41</b><i>b </i>and of the linkage of said ring with the chassis <b>40</b> are defined to assure sufficient mechanical strength to support the weight of the reservoir <b>3</b> filled with extinguishing agent and propelling agent.

p-0070The position of the ring <b>41</b><i>b </i>beneath the chassis is such that the intermediate position of the reservoir <b>3</b> corresponding to the position of said reservoir when it is suspended on said ring by its free hook-shaped end <b>31</b><i>b </i>is adjacent to the operational position.

p-0071The reservoir <b>3</b>, for example, has one or more rear metal fittings <b>301</b><i>a </i>positioned on the back side of said reservoir, and one or more front metal fittings <b>301</b><i>b </i>on the front side of said reservoir, whose geometries do not obstruct the vertical motion of the reservoir <b>3</b> to engage or disengage the free hook-shaped end <b>31</b><i>b </i>in the ring <b>41</b><i>b. </i>

p-0072In the non-limiting example shown in <figref idrefs="DRAWINGS">FIGS. 3</figref><i>b </i>and <b>3</b><i>c</i>, the reservoir <b>3</b> has two rear fittings <b>301</b><i>a </i>and one front fitting <b>301</b><i>b</i>. Each rear fitting <b>301</b><i>a </i>is in the form of a strap elongated upward, essentially parallel to the XZ plane, and has at least one hole for the passage of a fastener. The front fitting <b>301</b><i>b </i>forms a point of attachment for a first end of a connecting rod <b>5</b>, and has at least one hole for the passage of a pin to hold said connecting rod.

p-0073The hanger structure <b>4</b> in this case has two rear points of attachment <b>43</b><i>a</i>, which are in the shape of straps essentially parallel to the XZ plane in the non-limiting example shown in <figref idrefs="DRAWINGS">FIGS. 3</figref><i>b </i>and <b>3</b><i>c</i>, on which the rear metal fittings <b>301</b><i>a </i>of the reservoir <b>3</b> make contact, and a front point of attachment <b>43</b><i>b</i>, also in the form of a strap, to which is fastened a second end of the connecting rod <b>5</b>. The rear and front points of attachment <b>43</b><i>a </i>and <b>43</b><i>b</i>, respectively, also have one or more holes for the passage of fasteners or holding pins.

p-0074This particular embodiment of the metal fittings <b>301</b><i>a</i>, <b>301</b><i>b</i>, and of the hanger structure <b>4</b>, is beneficial in the case of a free hook-shaped end <b>31</b><i>b</i>, because said fittings do not obstruct the engagement and disengagement of said free end in the ring <b>41</b><i>b</i>. Fittings <b>300</b> of the type shown in <figref idrefs="DRAWINGS">FIGS. 2</figref><i>a </i>to <b>2</b><i>c</i>, making contact horizontally with the hanger structure <b>4</b>, are less advantageous since the engagement and disengagement of the free end <b>31</b><i>b </i>in the ring <b>41</b><i>b </i>necessitate placing the reservoir <b>3</b> in a superelevated position relative to the intermediate position, and such fittings <b>300</b> could interfere.

p-0075Other forms of metal fittings known to one skilled in the art can be combined with this embodiment of the means of suspension <b>31</b> and of the carriers <b>41</b>.

p-0076More generally, the embodiments of the means of suspension <b>31</b> and of the carriers <b>41</b> are not limited to the preferred embodiments described. In accordance with the disclosed embodiments, the means of suspension <b>31</b> and the carriers <b>41</b> must be complementary and permit suspending the reservoir <b>3</b> from the hanger structure <b>4</b>. It should be pointed out that because they are complementary, the forms of the means of suspension <b>31</b> and of the carriers <b>41</b> most often are interchangeable. For example, the carriers <b>41</b> can be in the form of a hook and the means of suspension <b>31</b> can be in ring form.

p-0077The embodiments in which the means of suspension <b>31</b> have a single free end are particularly advantageous because it is easier for an operator to adjust the position of a single free end relative to the carriers.

p-0078A method for suspending the reservoir <b>3</b> on a hanger structure <b>4</b> according to the disclosed embodiments comprises principally the following steps: <ul><li id="ul0001-0001" num="0000"><ul><li id="ul0002-0001" num="0078">a) a step for suspending the reservoir <b>3</b> on the hanger structure <b>4</b>,</li><li id="ul0002-0002" num="0079">b) a step for fastening the reservoir <b>3</b> to the hanger structure <b>4</b>.</li></ul></li></ul>

p-0079During step a) for suspending the reservoir <b>3</b>, the free end of the means of suspension <b>31</b> is engaged in the carriers <b>41</b> of the hanger structure <b>4</b>, and said reservoir is suspended in an intermediate position adjacent to the intended operational position, in which the metal fittings <b>300</b>, <b>301</b><i>a</i>, <b>301</b><i>b </i>of said reservoir are not put to work to hold the reservoir <b>3</b>.

p-0080In the case of means of suspension <b>31</b> that have a free T-shaped end <b>31</b><i>a </i>that interacts with carriers <b>41</b> of the type of a longitudinal guide <b>41</b><i>a</i>, the intermediate position is obtained, after engagement of the free T-shaped end <b>31</b><i>a </i>in the guide <b>41</b>, by moving the reservoir <b>3</b> longitudinally along the guide.

p-0081During step b) for fastening the reservoir <b>3</b>, the axes of the different holes in the metal fittings <b>300</b>, <b>301</b><i>a</i>, <b>301</b><i>b </i>of said reservoir and the corresponding holes in the hanger structure <b>4</b> are aligned to permit the passage of fasteners of known type. With the reservoir <b>3</b> held in the intermediate position, the fasteners can be put in place individually and then tightened progressively without the reservoir <b>3</b> being at risk of becoming unhooked.

p-0082When the axes of said holes are essentially vertical, as is the case, for example, in the example of the fittings <b>300</b> considered in the example shown in <figref idrefs="DRAWINGS">FIGS. 2</figref><i>a </i>to <b>2</b><i>c</i>, the alignment is obtained while keeping the reservoir <b>3</b> suspended on the hanger structure <b>4</b>.

p-0083When the axes of said holes are essentially horizontal, as is the case, for example, in the example of the fittings <b>301</b><i>a </i>considered in the example shown in <figref idrefs="DRAWINGS">FIGS. 3</figref><i>a </i>to <b>3</b><i>c</i>, the alignment may necessitate a slight tilting of the reservoir <b>3</b> (superelevation of the order of a centimeter), which is then no longer suspended on the hanger structure <b>4</b>.

p-0084When the fittings <b>300</b>, <b>301</b><i>a</i>, <b>301</b><i>b </i>are fastened to the hanger structure <b>4</b> and the reservoir <b>3</b> is in its operational position, the means of suspension <b>31</b> of said reservoir are engaged without contact and are no longer mechanically working.

p-0085Removing a reservoir <b>3</b> fastened to a hanger structure <b>4</b> comprises a step during which the fasteners are withdrawn, so that said reservoir is in its intermediate position, and a step during which the reservoir <b>3</b> is withdrawn.

p-0086Because of the means of suspension <b>31</b> of the reservoir <b>3</b> and the carriers <b>41</b> of the hanger structure <b>4</b>, said reservoir is placed adjacent to its operational position in said hanger structure with little effort, which in particular improves the convenience and safety conditions during the installation and removal of each reservoir <b>3</b>, and may permit the installation and removal of each reservoir <b>3</b> by a single operator, where the reservoirs known to one skilled in the art might necessitate the presence of at least two operators.